These are good reasons for trying to get some kind of analytic hold on the problems that Apple's recent troubles have caused.

If you are an Apple shareholder then lost sales matter, particularly when they are associated with a share price decline. You should be able to pass judgment on management, and management need to learn from their mistakes. Sales of the iPhone 5 have been great but could have been better.

Another reason is less to do with Apple and more to do with understanding the dynamics of online reputation. Apple is creating legacy reputation problems that impact revenues and share price.

Chris and researcher Sarah French did a new, flash study of Apple sentiment just after Mapplegate.

Here are some findings:

1. In the week beginning 21st September there were over 7 million online references to Apple, over 600,000 of which referred directly to Maps

2. Sentiment around Maps was of course much more negative than general sentiment towards Apple but in fact sentiment had two specific impacts on Apple, sales and reputation. Critics expressed a clear preference for Google Maps in this commentary, with over 10% of all comments regarding maps being a direct vote for Google.

3. Many people who expressed negative sentiment also expressed regret at upgrading to iOS 6

"A structured message analysis indicated that a significant proportion of commentators regretted purchasing the iPhone 5, or upgrading to iOS 6. A number of others said that they wouldn’t be upgrading their current Apple devices until the maps problem had been resolved, or advised others not to do so."

Human analysis of a sample of posts suggests that about 50% of negative posts also expressed regret at upgrading. Chris and Sarah conclude:

Our analysis also discovered that a significant proportion of the negative sentiment carried an additional weight in expressing not only disappointment with Apple, but also in positioning an explicit intention – to cancel or defer a purchase, or to recommend the same to others.

4. Finally, Chris and Sarah analyzed sentiment around Tim Cook's apology. They found no positive sentiment around this act at all.

A major theme was that Apple had put profit ahead of the user experience and that Jobs would not have allowed this to happen. Whether you agree with that sentiment or not, the surprise remains that there was so little positive reaction to Cook's apology.

What to conclude? If you happen to be the world's most successful tech company then for sure you can brush off some degree of negative sentiment.

When sales are growing, lost sales can appear irrelevant. But the writing is on the wall for Apple - it can turn people off the brand through no reason other than its own actions. That has to be a worry when you see your share price dip. How serious can it get?